The campaign was due to start on Thursday with officers teaming up with trading standards officers to visit nightclubs and pubs.

The operation follows a recent crackdown on off licences in the city.

Inspector Paul Mogg said: "I would urge that licensees remain vigilant and always insist that people show identification."

The joint operation will used 14 and 15-year-old volunteers who will work with undercover officers.

Anyone who is found guilty of serving an under 18 could be fined �1,000 or face six months in prison.

Roger Pope from Trading Standards said: "The anti-social behaviour that often results from underage drinking can directly impact on innocent members of the community."